The present invention relates to the field of angioplasty. In particular, the present invention relates to an intravascular perfusion catheter. The perfusion catheter is a dilatation balloon catheter, which provides both distal and side branch perfusion, and may be used for rapid exchange procedures.
Angioplasty procedures have gained wide acceptance in recent years as an efficient and effective method for treating certain types of vascular diseases. In particular, angioplasty is widely used for treatment of stenosis in the coronary arteries, although it is also used for treatment of stenosis in other parts of the vascular system.
The most widely used form of angioplasty makes use of a dilatation balloon catheter to treat a stenosis, and thereby reestablish an acceptable blood flow through the artery. The dilatation catheter includes an elongated tubular shaft and an inflatable balloon carried at a distal end of the shaft.
In operation, the catheter is inserted through a hollow guide catheter, which has been previously introduced into a patient's vascular system from a location remote from the heart (e.g., femoral artery). The proximal end of the guide catheter remains outside of the patient, while the distal end of the guide catheter is positioned at the ostium of the coronary artery to be dilatated.
A dilatation catheter is introduced into the proximal end of the guide catheter and advanced to the distal end of the guide catheter. Then, using fluoroscopy, the physician guides the dilatation catheter the remaining distance through the vascular system until the balloon is positioned across the stenosis therein. The balloon is inflated by supplying fluid under pressure through an inflation lumen in the catheter to the balloon.
The inflation of the balloon causes a widening of the lumen of the artery to reestablish acceptable blood flow through the artery. After a short inflation period, the balloon is deflated and the arterial treatment is evaluated to determine whether the procedure has reestablished an acceptable blood flow. If necessary, the dilatation procedure is repeated with the catheter balloon being reinflated.
Dilatation balloon catheters occlude blood flow while the balloon is expanded in the coronary artery. The balloon may be expanded for only a short inflation period, since occlusion of the coronary artery for extended periods may result in damage to portions of the heart which should receive blood from the occluded artery. Lack of blood circulation can lead to myocardial ischemia and angina, or anemic necrosis of tissues already stressed by the previously reduced level of blood flow.
One solution to allow extended inflation periods for complete treatment of the stenosis is the use of perfusion catheters. Perfusion catheters provide a path for blood to flow past the balloon, while the balloon is in an inflated state within the blood vessel. Thus, blood can be supplied to areas downstream of the inflated balloon during treatment of the stenosed artery.
U.S. Pat. No. 4,581,017 to Sahota suggests a perfusion catheter which includes a tubular shaft having a guide wire and perfusion lumen, and an inflation lumen. A dilatation balloon which communicates with the inflation lumen is carried at the distal end of the shaft. The tubular shaft includes at least one opening on the proximal side of the balloon and at least one opening on the distal side of the balloon, which communicate with the guide wire and perfusion lumen. When the balloon is inflated, blood may flow past the balloon by flowing through the proximal opening, through the guide wire and perfusion lumen, and out the distal opening.
Other perfusion catheters include a separate conduit for allowing blood to flow past the inflated balloon, such as is suggested in U.S. Pat. Nos. 4,983,167 and 5,147,377 to Sahota, U.S. Pat. No. 5,078,685 to Colliver, and U.S. Pat. No. 5,383,890 to Miraki et al. The perfusion conduits extend either through the dilatation balloon or along the outside of the dilatation balloon.
It is desirable to provide a dilatation balloon catheter which allows relatively high volumes of blood to flow past the balloon to a location distal of the balloon while the balloon is in an inflated state. Additionally, it is desirable to provide a perfusion catheter which allows blood flow to both distal and branch arteries. It is also desirable to provide a perfusion catheter which is low profile, and may be used in rapid exchange procedures.